Method of manufacturing turbines



' v 1,621002 March P. c. DIMBERG METHOD OF MANUFAGTURING TURBINES FiledAfaril- 1924 Patented Mar. 15, 1927."

. UNITED STATES I 1,621,002 PATENT OFFICE. Y

.PAUL G. DIMBEIBG, OF- WAUWATOSA, WISCONSIN, ASSIGNOR '10 ALLIS-CHALHERSMANUFACTURING COHPANY, OF MILWAUKEE, WISCONSIN, CORPORATIQN- OF nmwm.

duplication filed Anril a,

This invention relates generally to improvements in the art ofassembling and permanently. uniting elements in predetermined relationto each other, and relates more specifically to an improved method ofand means for rigidly connecting a plurality of definitely positionedturbine blades.

An object ofthe invention is to providean improved method of unitingturbine blades or the like into segments or complete rings of blades.

Prior to the present improvement, it was ordinary commercial practice toassemble and permanently unite turbine blades into segments, byattaching a shrouded segment to corresponding ends 'of a plural ty ofradially disposed blades, and by subseuently attaching a foundationsegment to t e opposite ends of the blades. The shroud and foundationsegments were in some instances attached by fusion of metal, as bybrazing, soldering, welding or casting. When casting the foundationsegments upon the root ends-of the blades, it was customary to use aramming key to pack the sand adjacent to the blade 'roots. With, such akey it was difficult to obtain smooth passages between the blades of thecompleted segment, and it was also diflicult to secure maximum strengthof the blades directly adjacent to the foundation segment.

The present invention contemplates provision of an improved method ofuniting theblades into segments, whereby smooth passages between theblades of the completed segment are readily obtainable. The lmprovemethod further contemplates provision of'means whereby the blades arestrengthened at their roots. With the im-- rovedmethod the manufactureof turbine lade se ments is also facilitated by eliminating the used aramming key, and the cost of production is reduced to a minimum. Theseand other objects and advantages of the present improvement will beapparent in the course of the accompanying escription. I Some of thenovel features of turbine blade se ent manufacture, disclosed but 5notspeclfically claimed herein, form the -subject-=of copendingapplications. A clear conceptionof the venous steps of the improvedmethod and of the con- HETHOD OF MANUFACTURING TURBINES.

1924. .Serial No. 705,182.

bling jig showing a plurality of blades? disposed and clamped therein.

Fig. 2 is a section through the assembling jig of Fig. 1, showing bladesassembled and clamped therein.

Fig. 3is a plan view of a blade se which has been temporarily but r1idly assembled preparatory to receiving a foundation segment.

Fig. 4 is\,a section through a core box used for preparing a temporarilyassembled blade segment for the reception of a foundation segment. 1 a

Fig. 5 is a section through a mold showing a sand' packed blade segmentdisposed therein preparatory to casting a foundation segment thereon.

Fig. 6 is a plan viewfofa completed blade ent segment directly after thesame has been removed. from the mold after casting a foundation segmentthereon.

Flg. 7 is a section through a' blade seg- 'ment which has beencompletely finished and applied to the supporting structure of aturbine. I

In the commercial exploitation of the im: proved method of manufacturingturbine blade segments, a blade assembling jig such as shown in Figs. 1and 2, is first .provided.

plate 10 having a substantially 'plane upper surface and a curved endsurface 12 extending substantially perpendicular to the plane surface; asegmental top plate 6 adapted to be secured to the bottom plate 10 bymeans of studs 27 and nuts associated therewith and having a resilientblade holding strip 11 attached to the lower face of the overhangingportion thereof; a base strip clamping plate 9 secured toan end face ofthe bottom plate 10 by means of a series of clampingscrews'; ,and .aseries of radially disposed clamps 8 extending through opeliings in thebottom plate 10 and having lat- -This jig consists of a segmental bottomof the clamps.

erally bent outer ends and threaded inner ends cooperable' with nuts foradjustment The blades 2 which are adaptedto be assembled in theassembling jig, ordinarily have uniform cross sectional areath'roughouttheir'lengths and are accu-- rately cut to predetermined size withnotches t in their corresponding longitudinal edges. The shroud segments3 are ordinarily formed of channel shaped-cross section andare notchedto receive the adja cent -blade endsjat the predetermined spacing andangle. The base strip 5 is rovided with a series of perforations w ichare properly spaced .and angled to hold the blades 2 inserted therein,in properly spaced and angled position relatively to a shroudsegment 3.The perforations in the strip 5 are preferabl slightly larger than theblade sections or reasons to be later explained. I

When assembling the blades in the assembling jig, the top plate 6 isfirst released sufiiciently to permit insertion of the rootends of theblades between the bottom plate 10 and the resilient strip 11. A basestrip 5 may then be clamped against the end surface of the bottom plate10 with the aid of the clamping plate 9, whereupon the blades 2 may bepassed endwise'through the perforations of the strip 5, the root ends ofthe wise shifting of the blades.v The plate 6' may then be forced intoclamping osition with the aid of the nuts and studs 2 causing rigidclamping of the blades, 2 and the strips '3, 5 within the 'ig. While theblades 2 and the associated e ements are thus positively held inproperly. spaced and angled position, the shroud strip, 3 may be. riidly and permanently attached to each 0 I the blades by brazing,welding, soldering or otherwise. The base strip 5 may also be rigidlylocall blades 2 as in icated at 13 in Fi ,3, by brazing, welding,soldering or the 'ke. When .the shroud and base stri s 3, 5 have beenthus permanently attach .to th eblad es, the

blades 2 are rigidly united to produce a uni-" tary segment and may beremoved from the assembling jigupon release of the top plate. 6,clamping plate 9 and clamps 8. The

work of temporarily assembling and uniting the blades 2 into segments,may be accomphshed by experts in this particular art, and the assemblingjig may be utilized to rapidly assemble successive segments attached toseveral of the The temporarily but rigidly united blade segmentsconsisting of the radially disposed properly spaced and angled blades 2,

the shroud segment 3, and the base strip 5,

shown in Fi 3, may then be transferred to the'foundry' eing ready toreceive-the permanent foundation segment. In the foundry, each segmentmust first be prepared for casting. For this purpose a core box such asshown in Fig. 4 is provided, the core box consisting of a bottom section15 'and a top section 14, these sections being provided with anintervening space adapted to conveniently receive a'temporarilvassembled blade segment. Each temporarily assembled blade segment isfirst placedin the recess of the lower section15 of the core box and'the space between the successive blades 2 and between the shroud andbase strips 3, 5 is completely filled with sand 16, the sand being wellpacked into this space. The top section 14. is then applied toproduce acore of definite size, whereupon the sand packed segment is ready forinsertion in a mold.

. With the aid of a suitable pattern, a mold such as disclosed in Fig. 5is then provided, the mold consistingof a cope 17 and drag 18 having agate 19 communicating with a segmental space 20. With a sand packedblade segment inserted within the mold as shown in Fig. 5, the segmentalspace 20 surrounds.

the root ends of the blades 2 which project beyond base strip 5'. -Thegate 19 is preferably located intermediate the ends of the segmentalspace 20 so that the metal is not undesirably chilled before it reachesthe extreme ends of this space. The metal is poured through the gate 19to the space 20 and completely surrounds the projecting root ends of theblades 2 and fuses with these blade ends as well as with the exposedsurfaces of the strip 5. By virtue of the factthat the erforations inthe strip 5 are made slightly arger than the cross sections of the.blades 2, the metal also passes through the s ace between theseperforations and the: b ades 2 and travels a slight distance along theblades to form a fillet at each blade 2 where it enters the strip 5.During the cast ing"operation,-the strip 5 expands slightly, but thestrip is returned to normal condition during cooling and shrinkage ofthe castin g'g The blade segment with the foundation segment 21 attachedthereto by fusion of metal after removal from the mold, is shown in Fig.6, this segment being ready to receive 5 a bracing or lacing strip 26which is applied in. the notches 4 and is attached to the blades in anysuitable manner as by brazing, welding or soldering. With the segmentthus completed, the same is ready for final finishing preparatory toapplication thereof in a turbine. The finishing of the segment is ac:comphshedin any convenient manner, the

- f -finished segment/being provided with a-Qseg mental groove; 23', andin ome instances "haw ing one side of the channel shaped shroud 3 bentasindicated at 25. The groove 23 is "adapted to coact wi-th'a tongueformed on asupporting element 22, proper -coa ction between theftongueand groove-being maintained by means of a calking strip 24-as shown inFig. 7. r 1

It has been, foundthatthe base strips provide absolutely smooth passagesbetween the blades 2 adjacent tothe foundation segments21. Thesestrips'5, besides-properly spacing and-angling the blades, also provide'relatively'f greater strength for the blades 2 at their root ends,where'strength fusion of metal, such fusion being accomplished byselecting proper materials for the] has been .found essential. -Theuseof the base strips 5 also facilitates manufactureof the segments. byeliminating the'use of ramming tools for packing the sand, and per-..

mits formation of the steam passages of any desired shape, dependingupon the shaping and disposition of the strips 5. It, has also. beenfound that the strips 5 may be readily attached to the foundation.segments 21- by strips 5 and the" foundation segments 21;

a It will" be obvious that elements other than of such elements t andpermanently attaching said stri turbine blades ma "be readily assembledand united with the aid ofthe present improvement, to produce a moreeflicient assemblage at miminum cost of production. It should beunderstood that it is 'not desired to limit the invention to the exactsteps of the process and to the exact details of construction andoperation of the apparatus herein shown 'and' described, for' variousmodifications within the scope of the claims may occur to personsskilled in the art.

It claimed and desired to secure by Let-- ters Patent:

1. The method of assembling turbine blades, which comprises, providing astrip .having perforations slightly larger than the larger than thecross-sectional area'of. thefblades, assembling the blades in said stripsome of saidblades, permanently attac ing the bladesjand casting afoundation around the'iient-endsofitheassembled' lades and in the fiiaceBetween said perforations and said .bla j r 3. The method I ofassembling turbine blades, which comprises? providing a perfosaid strip,permanently attaching some of said blades only to said strip at saidperforations, permanently uniting the ends-of all of said blades remotefrom said strip,iand cast ing a foundation segment around the root,

ends of said blades and in contact with-said strip.

rated strip of proper dimensions, assembling a plurality of bladesin theperforations of a 4. The method of assembling turbine I blades, whichcomprises, providing a perforated strip of properdimensions, assemblinga-pluraht'y off-blades in the perforations of said strip,-permanentlyuniting the ends 'of said blades remote. from said strip by attaching ashroud strip thereto, and casting a foundation segment around the rootends of said'blades and in contact with said strip.

5. The .method of assembling turbine blade segments, which comprises,providing a perforated segmentalstmp, assembling a plurality 'ofbladesin the perforations of said strlp, brazing a shroud segment to the endsof said blades remote from said strip,

permanently. attaching said strip to some of said blades only, andeasing a, foundation segment around the root ends of said blade and incontact-with said strip).

6. The method of assem ling turbine blade segments, which comprises,providing a perforated segmental strip, assembling a plurality of bladesin the perforations of said strip, permanently. attaching a shroudsegment, to correspondin ends of the blades,

tion segmentaround the root ends of the blades and in directcontact'withsaid strip."

7. The method of assembling turbine permanently attaching t e perforatedstrip to some of the blades, and casting a founda- V blades, whichcomprises, permanently unit-.

ing corresponding ends of a plurality of blades by attaching a shroudstrip thereto,- applying the blades adjacent to their root ends to theperforations of abase strip, casting a. foundation segment around theroot ends of the base and in contact with said base strip, andsubsequently attaching a lac ing strip to said blades intermediate theirends.

inventor is afiixed heret PAUL o. 'nmnnae. f

In testimony whereof, the signature ofthe v

